What is a radiotelescope?

A radiotelescope is a device for measuring radio frequency energy from
the cosmos. Radiotelescopes come in hundreds of configurations. The
aim of this tutorial is to introduce you to a very generalized type called
the total power radiotelescope. It is probably the type of radiotelescope
most often used by amateur radio astronomers, but many total power radiotelescopes
are also in use by professional observatories. We have eliminated
all the bells and whistles (some of which are important like a calibrator),
in the interest of providing a general understanding without swamping you
with information. There is no math or serious electronics here.

Click on a component in the picture above for a functional
description.